The role of P fimbriae for Escherichia coli establishment and mucosal inflammation in the human urinary tract

Int J Antimicrob Agents. 2003 Jun;21(6):605-21. doi: 10.1016/s0924-8579(02)00328-x.


Bacterial adhesion to the bladder mucosa is a critical step for the establishment of Escherichia coli bacteriuria. The P-fimbriae, encoded by the pap gene cluster, are considered as virulence factors but the mechanisms have been debated. This study defined the roles for P fimbriation during the early colonization of the human urinary tract. Patients with recurrent UTI were first subjected to deliberate colonization with the non-fimbriated ABU strain E. coli 83972. Bacteriuria was established long term (1-4 years) in patients with dysfunctional bladders, but not in the patients with normal bladder function. Super-infections were transient and asymptomatic. P fimbriated transformants of the ABU strain (E. coli 83972pap+/prs+) reached 105 CFU/ml more rapidly than E. coli 83972 and the vector control. This was demonstrated by group wise and intra-individual analysis in patients colonized on different occasions with E. coli 83972 or the P fimbriated transformants. Higher neutrophil numbers and IL-8 and IL-6 concentrations in urine were obtained after colonization with the P fimbriated transformants. These results demonstrated that transformation of E. coli 83972 with the pap sequences is sufficient to convert it to a more potent host response inducer. The P fimbriae were shown to lower the significant bacteriuria threshold. The P fimbriated transformants needed lower bacterial numbers (103-4 CFU/ml) to predict a positive second urine culture with a >80% accuracy and to trigger a significant host response. These studies show that P fimbriae fulfil the Koch Henles molecular postulates for bacterial establishment and host response induction in the human urinary tract.

Publication types

  • Corrected and Republished Article
  • Review

MeSH terms

  • Escherichia coli / pathogenicity*
  • Escherichia coli Infections / microbiology*
  • Escherichia coli Infections / pathology
  • Female
  • Fimbriae, Bacterial / physiology*
  • Humans
  • Inflammation / microbiology
  • Inflammation / pathology
  • Male
  • Mucous Membrane / microbiology
  • Mucous Membrane / pathology
  • Urinary Tract / microbiology*
  • Urinary Tract / pathology
  • Urinary Tract Infections / microbiology*
  • Urinary Tract Infections / pathology